The island where Vancouver International Airport is located is located in Richmond.
Richmond downtown is about 7 kilometers away from Vancouver International Airport, and Vancouver downtown is about 15 kilometers away from the airport.
It's convenient to get to the airport from downtown Richmond or downtown Vancouver, because there are air trains. Among them, you have to transfer from Richmond to the airport, but the distance is much closer and the air ticket is much cheaper. From Vancouver to the airport, you don't have to change cars, but it's a long way and the air ticket is expensive.
Shopping in downtown Vancouver is good; Eating in downtown Richmond (especially Chinese food) is very good.